1. Field of the Invention
The present invention relates to handling bulk product such as agricultural produce, in particular grain or other similar products, that can also contain a powder component referred to hereinafter as "dust".
The invention relates more particularly to a device for laying dust contained in a flow of bulk product during transfer thereof.
Transfer can be effected in order to fill or empty a silo, a transportation vehicle such as a railroad wagon, truck or grain bulk-carrier ship or a storage heap. The invention finds one particularly useful application in cells of a silo for storing grain and in ducts for transferring grain to a storage area or transport vehicle.
The presence of dust in bulk product can be a great nuisance because dust that separates from the product during transfer forms a suspension in the air and can then degrade the cleanliness of the storage place or the environment. In the case of grain silos, the dust can even cause risks of fire or explosion, similar to those associated with coal "dust", for example.
2. Description of the Prior Art
In the dust-laying device described in U.S. Pat. No. 2,973,740, a divergent cone is placed in a casing which, as seen in the direction of flow of the product, narrows until the product enters a pipe connected to the dust-laying device. The layer of product formed downstream of the divergent cone is therefore obliged to become narrowed along the inside surface of the casing. This retards the forward movement of the layer, which reduces the flowrate at which the product passes into the dust-laying device. Also, the structure of the above prior art dust-laying device soils readily because as it moves forward the product is confined within an increasingly small space. Finally, the spray device is housed inside the cone and therefore cannot spray directly onto the outside envelope of the layer, but only from the interior of the divergent cone. It is also found that the above prior art device retards the flow of the product downstream of the spray area, which can become completely invaded by the product if the downstream flow is stopped.
The object of the invention is to provide a device for laying dust contained in a bulk product which remedies the drawbacks of the prior art dust-laying device.